1. Field of the Invention
This invention relates generally to an ultrasonic diagnosis system and more particularly, to a ultrasonic diagnosis system which makes it possible to measure the acoustic velocity inside the body of a subject.
2. Description of the Prior Art
Studies on tissue characterization have been vigorously made in recent years in various countries and the measurement of acoustic velocity is a critical problem. The conventional methods of measuring the acoustic velocity include a singaround method and ultrasonic computer tomography. Since they are transmission methods, however, there is an inevitable limit to measuring the acoustic velocity inside the body of a subject.
On the other hand, the measuring methods of the reflection type include one that radiates ultrasonic beams from two directions to a body within a coupling tank containing an acoustic coupling liquid so as to analyze the refraction at the interface between the living body and the acoustic coupling liquid. However, this method involves the problems that incident angles at the interface should be accurately measured and that the calculation is complicated.